Furnace blows cold air before finally kicking on — normal or a problem?

Get asked this a lot going into colder months. A short delay (10-30 seconds of blower running before you feel heat) is completely normal — that's the sail switch confirming airflow before the burner's allowed to ignite, a safety feature, not a fault.

Worth actually checking if: the delay is a full minute or more, it cycles that way every single time rather than just on cold starts, or it never catches at all and just blows cold. Those point at a dirty sail switch, weak igniter, or low battery voltage (furnaces are more voltage-sensitive than people expect since the igniter and fan both draw real current at startup).

How long's the delay you're seeing, and is it consistent or getting worse?